Editing Blindsight (section)

==== Alexander and Cowey ====
Alexander and Cowey investigated how contrasting stimuli brightness affects blindsight patients' ability to discern movement. Prior studies have already shown that blindsight patients are able to detect motion even though they claim they do not see any visual percepts in their blind fields.<ref name="Weiskrantz" /> The study subjects were two patients who suffered from [[hemianopsia]]—blindness in more than half of their visual field. Both subjects had displayed the ability to accurately determine the presence of visual stimuli in their blind hemifields without acknowledging an actual visual percept previously.<ref name="Alexander and Cowey">{{cite journal|vauthors = Alexander I, Cowey A|title = Isoluminant coloured stimuli are undetectable in blindsight even when they move|journal = Experimental Brain Research|volume = 225|issue = 1|pages = 147–52|date = March 2013|pmid = 23263562|doi = 10.1007/s00221-012-3355-6|s2cid = 1738371}}</ref>

To test the effect of brightness on the subject's ability to determine motion they used a white background with a series of colored dots. The contrast of the brightness of the dots compared to the white background was altered in each trial to determine if the participants performed better or worse when there was a larger discrepancy in brightness or not.<ref name="Alexander and Cowey" /> The subjects focused on the display for two equal length time intervals and were asked whether they thought the dots were moving during the first or the second time interval.<ref name="Alexander and Cowey" />

When the contrast in brightness between the background and the dots was higher, both of the subjects could discern motion more accurately than they would have statistically through guesswork. However, one subject was not able to accurately determine whether or not blue dots were moving regardless of the brightness contrast, but he/she was able to do so with every other color dot.<ref name="Alexander and Cowey" /> When the contrast was highest, subjects were able to tell whether or not the dots were moving with very high rates of accuracy. Even when the dots were white, but still of a different brightness from the background, subjects could still determine whether they were moving. But, regardless of the dots' color, subjects could not tell when they were in motion when the white background and the dots were of similar brightness.<ref name="Alexander and Cowey" />